Photographic web processing

ABSTRACT

A WEB PROCESSING METHOD OBTAINS A SILVER IMAGE BY DEVELOPING AN EXPOSED SILVER HALIDE EMULSION LAYER BY LAMINATING THE EXPOSED LAYER TO A PROCESSING SHEET HAVING IMIBED THERIN A PROCESSING SOLUTION CONTAINING A STABLILIZING AGENT WHICH FORMS A SUBSTANTIALLY WATER INSOLUBLE SILVER SALT COMPOUND. THE RESULTING INTEGRAL ELEMENT PERMITS CONVENIENT HANDLING AND VIEWING OF THE IMAGE.

March 30, 1971 a. K, BOLLER Erm. 3,573,048

' PHOTOGRAPHIC WEB PROCESSING Filed Jan. 3l. 1968 GELA//v LAYER-fk \\\f/2 PHOTUGRAPH/c EMULS/o/v-fG/x( 7 |\\\\\\\\\\\\\\\Y///// ,f7/EHI /MA @E E/LLY KBO/.LER

EDWARD A. SMITH- ALLAN L, SOREM INVENTORS A TTORNE Y United States Patent O 3,573,048 PHOTOGRAPHIC WEB PROCESSING Billy K. Boller, Edward A. Smith, and Allan L. Sorem,

Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, NY.

Filed Jan. 31, 1968, Ser. No. 701,971 Int. Cl. G03c 5/38 U.S. Cl. 96-61 16 Claims ABSTRACT F THE DESCLSURE A web processing method obtains a silver image by developing an exposed silver halide emulsion layer by laminating the exposed layer to a processing sheet having imbibed therein a processing solution containing a stabilizing agent which forms a substantially water insoluble silver salt compound. The resulting integral element permits convenient handling and viewing of the image.

This invention relates to photographic processing in which an exposed radiation sensitive emulsion layer is intimately contacted with a hydrophilic processing layer or web containing an aqueous processing solution. More particularly, this invention relates to a processing sheet and element obtained by laminating the sheet to an exposed photographic emulsion on a support to form an image area and a substantially water insoluble silver compound non-image area at least one of the support or sheet being transparent.

For many purposes, such as for processing aerial photographs, it has been desirable to dispense with conventional photographic processing solutions which spill easily, etc. For instance, an exposed silver halide emulsion can be processed by contacting the emulsion against a hydrophilic processing layer or web which has been imbibed with an aqueous processing solution containing a silver halide developer as described in U.S. Pat. 3,179,517, issued Apr. 29, 1965, to Tregillus et al. In one embodiment of the process, the processing sheet also contains imbibed therein a silver halide solvent and a nucleating agent. As a result, a positive image is obtained on the processing sheet and a negative image obtained in the silver halide emulsion. In order to study the positive image, the processing sheet is separated from the silver halide emulsion. However, the emulsion and the processing sheet have sticky surfaces and are somewhat inconvenient to handle. Therefore, it has been desirable to obtain a photographic element which could be handled conveniently but which would have the advantages previously obtained by using the processing sheet method.

In attempts made to provide improved handling of photographic elements which contain processing solutions obtained by processing, by leaving the processing sheet laminated to the emulsion, several problems have been experienced. For instance, satisfactory lamination between the web or processing sheet and the photographic emulsion layer has not been obtained; moreover, a satisfactory density relationship between the background areas and the image areas has not resulted. There has also been a problem with regard to stability with certain stabilizing agents.

Therefore, it has been desirable to find a means of conveniently stabilizing the processed silver halide emulsion against darkening and particularly to provide low densities in non-image areas while at the same time providing a cover sheet which can be satisfactorily laminated to a silver halide emulsion and which insures stabilization long enough to enable the image to be studied.

Conventional processing sheets or Webs having a gelatin coating thereon and containing processing agents have 3,573,048 Patented Mar. 30, 1971 ICC been found to be unsatisfactory with respect to lamination and delaminate too readily for satisfactory use during handling operations such as rewinding on a viewer, threading and similar uses. Therefore, rapid adhesion of the processing sheet was desired to provide satisfactory lamination.

With conventional processing solutions and a typical nucleated processing sheet, positive images are obtained in the sheet. For instance, when sodium thiosulfate is employed as the silver halide solvent, a positive image is obtained in the sheet, particularly when the sheet is nucleated, as well as a negative image in the emulsion layer. Ii the sheet is nucleated, the positive image typically has a density greater than that of the negative image, making it dii-heult to distinguish between the two images when viewing through transparent supports. If certain agents such as monothiohydroquinone or thiosalicylic acid are used which form an opaque insoluble silver compound, formation of a positive image is avoided, but the negative image has a minimum density above 0.40 which is not entirely satisfactory for viewing through transparent supports. Accordingly, it has been preferable in the non-image areas to provide a density suiciently low, i.e., no greater than 0.50 to provide a viewable image when the supports for the emulsion and the processing layer are both transparent and to avoid forming a positive image with either a nucleated or non-nucleated processing sheet.

The processing solution should also be useful in those instances Where either an opaque support or a transparent support is used for the silver halide emulsion and processed by using an imbibed processing sheet which is either opaque or transparent and is laminated to the silver halide emulsion in an integral relationship, provided that either the support for the emulsion or processing sheet is transparent.

We have now found that an exposed radiation sensitive silver salt emulsion can be prepared in an integral laminated form by contacting with a processing sheet having imbibed therein a developer and a stabilizer which forms a water insoluble silver compound. The lamination is provided which is secure enough to provide rapid access and convenient handling.

It is one ob ject of this invention to provide a processing method to obtain a negative image in an exposed radiation sensitive silver salt emulsion which can be handled conveniently and which results in an integral product with a processing sheet laminated to the emulsion. Another object is to provide a photographic element comprising in integral relationship a support having thereon a silver image area and a substantially water insoluble silver compound non-image area and having laminated thereover a transparent processing sheet. A further object is to provide a processing method for use with a nucleated processing sheet or web in which an image is formed only in the emulsion layer. A still further object is to provide a processing method employing a processing sheet containing a silver salt stabilizing agent which forms a substantially water insoluble silver salt compound such that the density of the undeveloped areas is no greater than 0.50. Another object is to provide a processing sheet or web which can be laminated to an exposed photographic emulsion resulting in rapid adhesion satisfactory for convenient handling. Additional objects will be apparent from the following disclosure.

In carrying out one embodiment of the invention a silver halide emulsion on a transparent support is exposed to a light image and contacted against a transparent sheet having thereon a gelatin coating with a melting point of about 240 F. The gelatin coating has imbibed therein an aqueous solution containing a silver halide developer such as hydroquinone and a silver halide stabilizing agent such as S-S-thiuronium propane sulfonate. The exposed emulsion is developed and stabilized and the transparent processing sheet is iirmly laminated to the surface of the silver halide emulsion. The silver image can be viewed through the transparent support of the negative element and through the processing sheet. The non-image areas have a density no greater than 0.50.

11n another embodiment of the invention, gelatin having a melting point of about 212 F., is coated over a silver halide emulsion after which the emulsion is exposed and contacted against a processing sheet as above `with good lamination results. Similar good results are obtained when the gelatin is coated under the emulsion.

In still another embodiment of the invention, a negative or positive image is obtained by known means and used to expose a silver halide emulsion which is then processed according to our invention. If the light image is obtained by employing a negative, then the integral element of our invention can contain a positive image.

Any suitable support may be used for the processing sheet or web provided that either it or the tilm support is transparent and preferably flexible. Particularly useful supports include: glass, polyesters, polyamides, poyethyene, polypropylene, polystyrene, polyethylene terephthalate, cellulose esters, paper, or the like.

The processing sheets or webs which are useful in our invention comprise a hydrophilic absorbent organic colloid layer on a suitable support. The colloid material should preferably be inert to the chemicals in the processing solution and should be capable of adhering readily to a silver halide emulsion layer, particularly a gelatin emulsion layer. The colloid material can be coated on the 'web in the range of about 200 to 3000 mg. per square foot preferably 1000 to 2000 mg. If a colloid layer is coated over the emulsion, the range is about 50 to 1000 mg. per square foot. If coated under an emulsion, the range is about 100 to 2000 mg. per square foot. It will be appreciated that if a colloid such as gelatin is coated on the support with the emulsion that it will preferably be coated under the emulsion. A thicker coating is practical and absorbs any excess processing solution. Moreover, it has little or no effect on image sharpness if the coating is under the emulsion. Suitable hydrophilic organic colloids include proteinaceous materials such as gelatin, casein, etc., polyvinyl alcohol, hydrolyzed cellulose acetate, cellulose ether phthalate, carboxylated rubber, and similar materials. A particularly useful hydrophilic material is gelatin, especially gelatin having a melting point in water of about 212 to about 240 F. However, mixtures of hydrophilic colloids may be used. A particularly useful mixture comprises gelatin and a copolymer made up of 80% acrylic acid and 20% ethyl acrylate.

As indicated above, processing sheets or webs which have been nucleated for use in the processing method in which a positive image is obtained in the processing sheet may also be used although a positive image is not obtained according to our invention. Typical nuclei which are used in preparing a nucleated sheet include silver precipitating agents such as suldes, selenides, polysulides, polyselenides, thiourea and its derivatives, mercaptans, stannous halides, silver, gold, platinum, pallidium, and mercury, colloidal sulfur, aminoguanidine sulfate, aminoguanidine carbonate, arsenous oxide, sodium stannite, substituted hydrazines, xanthates, and the like.

The degree of adhesion between the processing sheet and photographic tilm surfaces is evidence of the usefulness of the integral film element. The adhesion must be suicient to prevent delamination of the layers during handling operations such as rewinding on a viewer, threading and other similar uses. We have found that a suitable test for adhesion involves the force necessary to strip apart the processing sheet-film laminate, once they have been contacted together by moderate pressure such as manually, using rollers, etc., and then left in a laminated state with no pressure applied for 15 minutes.

To measure the force necessary to separate the sheet-film sandwich, the end of one of the pieces is attached to a spring balance. The corresponding end of the other layer is pulled at a slow steady rate in a delaminating direction. As the layers delaminate, the separating force is in the direction to the supporting force and the value of the tension required to maintain separation at a steady rate is observed. Values above 15 grams for 35 millimeter widths of iilrn have been found to be satisfactory, while values of 15 grams and less indicate insuicient adhesion of the two layers to permit satisfactory operation in a practical use.

The value of 15 grams is applicable to 35 millimeter film only. Since the magnitude of the force is dependent on the width of the laminated lilms, a value of 30 would be appropriate for 70 millimeter films.

The processing solution which is imbibed into the processing sheet preferably contains, as an alkaline agent, a solution of one of the organic amine-sulfur dioxide addition products employed as alkaline materials in the usual processing solutions. `In particular, the alkaline component is preferably an aliphatic hydroxyamine-sulfur dioxide addition product as described in U.S. Pat. 3,179,- 517. The alkaline component has an especially useful concentration of 50 to 400 parts per 1000 by weight. The solution also can contain a silver halide developer although the developer or part of the developer can be incorporated in the light sensitive emulsion, in which event all or part of the developer can be omitted from the processing solution. A particularly useful range of developer is from about 5 to 40 parts per 1000, by weight, but the amount can be varied above or below this range.

Particularly useful stabilizers for use in the processing solution which produce water insoluble compounds with good stability include the general class of soluble cornpounds represented by the formula R'SH, where R is any aliphatic, such as e.g. alkyl, alkylene, etc., or cyclic, such as aromatic, e.g. phenyl, naphthyl, heterocyclic, cycloalkyl, etc., group. Generally the soluble compounds have an R group which contains no more than 20 carbon atoms. Compounds formed with silver have a general formula RSAg. Other soluble compounds which form insoluble complexes, of course, may also be used. These stabilizers may be used separately or in combination. As already indicated, we do not prefer to use compounds such as monothiohydroquinone and thiosalicyclic acid, with photographic emulsions on a transparent support and a transparent processing sheet, which form relatively opaque salts and which do not forrn insoluble silver salts having a density no greater than about 0.501. In practicing this inveniton, it is understood that the stabilizing compounds must also be relatively stable when combined in a processing sheet containing silver halide developing agents and the like.

Suitable stabilizing agents include the compounds of Humphlett et al., U.S. Pat. 3,301,678, issued Ian. 3 l, 1967. The compounds are generally represented by the following formulas:

Formula A il R5 Formula C In the above formulas: R, R3, R8 and R12 are each lower alkylene radicals having 1 to 5 carbon atoms including methylene, ethylene, propylene, butylene, isobutylene, and amylene. R1, R2, R4, R5 and Rg are each hydrogen atoms, lower alkyl radicals having l to 5 carbon atoms or aryl radicals as described below for R6 and R7. R5 and R7 are each aryl radicals such as phenyl and naphthyl, and typically include substituted aryl radicals as illustrated by the radical having the formula wherein D is typically a nitro radical, a hydroxy radical, a chloro radical, a bromo radical, a lower alkyl radical hiving l to 5 carbon atoms or a lower alkoxy radical wherein the alkyl moiety has l to 5 carbon atoms. R1o and R11 are each cyano radicals, alkoxycarbonyl radicals wherein the alkyl moiety has l to 5 carbon atoms or amido radicals.

X is an anion or acid residue such as chloride, bromide, nitrate, trichloroacetate, perchlorate, formate, acetate, aminoacetate or the like. A is a hydroxy radical or a radical having the formula wherein R13, R14, R15, R15, R1'7 and R18 are each hydrogen atoms, lower alkyl radicals having l to 5 carbon atoms or an aryl radical as described for RS and R7, and X is an anion described above. M and Z are each hydroxy radicals, carboxy radicals or amino radicals including primary (-NH2) and secondary amino radicals, and more generally teritary amino ardicals such as morpholino, piperidino, pyrrolidino, and dialkyl amino wherein the alkyl moiety has l to 5 carbon atoms.

Suitable compounds within the scope of these generic structures include:

These include isothiourea derivatives represented by the general structures R1, R2, R3, R4, R5, R6 and R7 can be hydrogen atoms, hydrocarbon radicals such as aryl radicals as illustrated by phenyl radicals, alkyl-substituted phenyl and alkyl radicals and substituted alkyl radicals. R1 and R2 can also be acyl radicals having the formula O II RC- wherein R is an an alkyl radical. R1 and R2 together can be the necessary atoms to form a heterocyclic ring or preferably they can be the necessary carbon and hydrogen atoms to form an alkylene radical linking both adjacent nitrogen atoms to form a cyclic nucleus as illustrated by the following moiety wherein R8 is and alkylene radical;

I N Il;

wherein R3 can be an acyl radical in addition to those substitutents described above for R3. The letter n can be an integer generally 0 to 10, and preferably l to 3. The letter Y can be a carboxy radical,l a sulfonate radical, a hydroxy radical or an amino radical, including substituted amino radicals, of the formula:

wherein R9 is a hydrogen atom or an alkyl radical, and wherein R10 is a hydrogen atom, an alkyl radical or an acyl radical, their salts having the formula:

Ru MRW or a morpholino radical. Typical alkyl and alkylene radicals referred to above have l to 20 carbon atoms and more generally 1 to 4 carbon atoms. Illustrative alkyl radicals include methyl, ethyl, isopropyl, n-butyl, 2-ethylhexyl, n-decyl, stearyl, n-eicosyl and like radicals. Alkylene radicals analogous to such alkyl radicals are suitable R8 substituents. Suitable compounds Within the scope 0f this structure include, for example,

2-S-thiuronium ethane sulfonate:

/C-s-CIAnCI-Ig-s 01H HZN 3-S-thiuroniun1 propane sulfonate:

/C-s-(CH2)3-S 03H H2N 4-S-isothiur0nium butane sulfonate:

C-s-(CHm-s 03H HzN 3-S-isothiuronium methyl-propane sulfonate:

HN CH3 /Cs-CH2-CH2-cH-s 03H HzN In one embodiment the above compounds which contain a sulfonate radical and form so-called inner acid salts are preferred complexing agents. Inner acid salts as employed herein are defined in U.S. Pat. 3,220,839, Herz and Kalenda.

The stabilizing agents employed according to this invention are generally stable and substantially inert in acidic or neutral media and under temperatures that prevail during conventional storage and use of photographic products.

In addition to the above compounds, guanidinium-3- mercapto-propane sulfonate is a useful silver stabilizing agent as well as mercapto acetic acid, mercapto benzoic acid, etc.

The stabilizing agent can be used in a wide range provided enough is present to stabilize the undeveloped silver halide. The amount required will depend upon the specific silver halide emulsion used, the stabilizing agent, etc., but a typical range is from about 0.05 to 1.0 mole per liter of imbibed processing solution or aboutJS to about 300 parts by weight per 1000. Variations from this range are also useful.

Since the amount of processing solution imbibed into the processing sheet affects lamination, we have found that a particularly useful range for the processing solution absorption is about 3.5 to 6 grams per square foot.

The photographic silver salt emulisons which can be used in the practice of this invention include silver halide emulsions such as silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver chlorobromoiodide, etc.

The photographic silver halide layer employed in the practice of this invention is a photographic silver halide emulsion layer. It is preferred to use gelatin as a sole binding agent for the silver halide although other photographic binding agents for example hydrophilic colloids, proteinaceous materials such as zein, casein, etc., and the like, can be used to replace all or part of the gelatin. Suitable binding materials which can be used include for example, cellulose derivatives, synthetic resins, particularly polyvinyl compounds and the like. Water insoluble polymerizable vinyl compounds, particularly those known to improve dimensional stability can also be included, as exemplified by water soluble polymers of alkyl acrylate, methacrylate and the like.

The coverage of the silver halide emulsion can be varied within a very wide range. A useful range is about 100-800 mg. per square foot of gelatin, preferably 200- 600 mg. per square foot and about 50-500 mg. per square foot of silver or silver halide, preferably 50-350 mg. per square foot. The photo-graphic emulsions described herein can be chemically sensitized such as with compounds of the sulfur group, noble metal salts such as gold salts, reduction sensitized with reducing agents, combinations of these, etc. Furthermore, the emulsion and other layers can be hardened with any suitable hardener such as aldehyde hardeners, aziridine hardeners, hardeners which are derivatives of dioxane, oxypolysaccharides, such as oxystarch, oxy plant gums and the like.

The photographic silver halide emulsions can also contain additional additives particularly those known to be beneficial in photographic emulsions, including for example, stabilizers or antifoggants, particularly the water soluble inorganic acid salts of cadmium, cobalt, manganese and zinc as disclosed in U.S. Pat. 2,829,404, substituted triazaindolines as disclosed in U.S. Pats. 2,444,605 and 2,444,607, speed increasing materials, plasticizers, absorbing dyes and the like. Sensitizers which give particularly good results in typical emulsions useful in our invention are the alkylene oxide polymers which can be employed alone or in combination with other materials such as quaternary ammonium salts as disclosed in U.S. Pat. 2,886,437 or With mercury compounds and nitrogen containing compounds as disclosed in U.S. Pat. 2,751,299. The emulsions can be blue sensitized, orthochromatic, panchromatic, infrared sensitive, etc.

The silver halide emulsions used in practicing this invention include both negative and positive emulsions. Suitable positive emulsions which can be used include direct positive emulsions such as (1) solarizing silver halide emulsion and (2) internal latent silver halide emulsions forming the latent image mostly inside the silver halide grains.

The solarizing direct positive silver halide emulsions are silver halide emulsions which have been effectively fogged either chemically or by radiation, to a point which corresponds approximately to the maximum density of the reverse curve as shown by Mees, The Theory of the Photographic Process, published by Macmillan Co., New York, N.Y. 1942, pages 261-297.

Typical methods for the preparation of solarizing emulsions are shown by Groves British Pat. 443,245, Feb. 25, 1936, which describes subjecting an emulsion to Rontgen rays until the emulsion layer, when developed Without additional exposure, is blackened up to the apex of its gradation curve; Szaz British Pat, 462,730, Mar. l5, 1937, the use of either light or chemicals such as silver nitrate, organic sulfur compounds and dyes to convert ordinary silver halide emulsions to solarizing direct positive emulsions; Arens U.S. Pat. 2,005,837, June 25, 1935, the use of silver nitrate and other compounds in conjunction with heat to effect solarization of the silver halide, and Leerniakers U.S. Pat. 2,184,013 the use of large concentrations of non-acid optical sensitizing dyes and reducing agents to effect solarization.

Kendall and Hill U.S. Pat. 2,541,472, Feb. 13, 1951, shows useful solarizing emulsions particularly susceptible to an exposure with long wave-length light to produce a Herschel effect described by Mees above, produced by adding nitro-substituted electron acceptors and other compounds to the emulsion which is fogged either chemically or with white light.

In using solarizing emulsions, a sucient reversal image exposure is employed using minus blue light of from about 500-700 millimicrons wave-lengths, preferably 520- 540 millimicrons, to substantially destroy the latent image in the silver halide grains in the region of the image exposure.

Conventional silver halide developing solutions can be used to develop a direct positive image in solarizing emulsions.

The internal latent image direct positive silver halide emulsions used in this invention include those well known 1n the art which upon exposure form the latent image mostly inside the silver halide grains, the direct positive properties of the emulsions being attributable to the crystalline structure of the silver halide grains. That is, a number of authorities in the field of photography have shown that there are imperfections or flaws, in the crystal structure (on on the surface or internally) of silver halide which is used in photography, at which flaws the latent image forms by trapping photoelectrons to give development centers. Development, therefore, commences at the sites of these flaws. Journal of Photographic Science. Photographic Sensitivity, text of a lecture given on July 1, 1957, by J. W. Mitchell; vol. 6, No. 3 (1958). Other photographic reversal emulsions may be used including those containing grains comprising a central core of a water insoluble silver salt containing centers which promote the deposition of photolytic silver and an outer shell or covering for such core of a fogged or spontaneously developable water insoluble silver salt. The fogged shell of such grains is developed to silver without exposure. Emulsions of this type are described in Berriman U.S. patent application Ser. No. 448,467, filed Apr. 15, 1965.

Before the shell of water insoluble silver salt is added to the silver salt core, the core emulsion is first chemically or physically treated by methods previously described in the prior art to produce centers which promote the deposition of photolytic silver, i.e., latent image nucleating centers. Such centers can be obtained by various techniques as described in the prior art. Chemical sensitization techniques of the type described by Antoine Hautot and Henri Saubenier in Science et Industries Photographiques, vol. XXVIII, January 1957, pages 57-65, are particularly useful. Such chemical sensitization includes three major classes, namely, gold or noble metal sensitization, sulfur sensitization, such as labile sulfur compound and reduction sensitization, i.e., treatment of the silver halide with a strong reducing agent which introduces small specks of metallic silver into the silver salt crystal or grain.

The core emulsions can be chemically sensitized by any method suitable for this purpose. For example, the core emulsions can be digested with naturally active gelatin, or sulfur compounds can be added to those described in Shepard U.S. Pat. 1,574,944, issued Mar. 2, 1926, Shepard et al. U.S. Pat. 1,632,499, issued Apr. 5, 1927, and Shepard et al U.S. Pat. 2,410,689 issued Nov. 5, 1946.

The core emulsions can also be chemically sensitized with ygold salts as described in Waller et al. U.S. Pat. 2,399,083, issued Apr. 23, 1946, and Damschroder et al. U.S. Pat. 2,642,361, issued June 16, 1953. Suitable compounds are potassium chloroaurite, potassium aurithiocyanate, potassium chloroaurate, aurictrichloride and 2- aurosulfobenzothiazole methylchloride.

The core emulsions can also be chemically sensitized with reducing agents, such as stannous salts (Carroll U.S. Pat. 2,487,850, issued Nov. 15, 1949), polyamines such as diethylenetriamine (Lowe and Jones U.S. Pat. 2,618,598, issued Aug. 15, 1950), polymines such as spermine (Lowe and Allen U.S. Pat. 2,521,925, issued Sept. 12, 1950) or bis(betaaminoethyl) sulfide and its water soluble salts.

The shell of the grains comprising the emulsions used in practicing this invention is prepared by precipitating over the core grains a light-sensitive water-insoluble silver salt that can be fogged and which fog is removable by bleaching. The shell is of sufficient thickness to prevent access of the developer used in processing the emulsions of the invention to the core. The silver salt shell is surface fogged to make it developable to metallic silver with conventional surface image developing compositions. The silver salt of the shell is sufficiently fogged to produce a density of at least about 0.5 when developed for 6 minutes at 68 F. in Developer A below when the emulsion is coated at a silver coverage of 100 mg. per square foot.

DEVELOPER A Grams N-methyl-p-aminophenol sulfate 2.5 Ascorbic acid 10.0 Potassium metaborate 35.() Potassium bromide 1.0

Water to 1 liter. pH of 9.6.

Such fogging can be effected by chemically sensitizing to fog with the sensitizing agents described for chemically sensitizing the core emulsion, high intensity light and like fogging means well known to those skilled in the art. While the core need not be sensitized to fog, the shell is fogged, for example, reduction fogged with a reducing agent such as stannous chloride. Fogging by means of a reduction sensitizer, a noble metal salt such as gold salt plus a reduction sensitizer, high pH and low pAg silver halide precipitating conditions, and the like can be suitably utilized. The shell portion of the subject grains can also be coated prior to fogging.

Another direct positive silver halide emulsion which can be used is a fogged direct positive silver halide emulsion comprising fogged silver halide grains which have a uniform diameter frequency distribution, i.e., silver halide grains which have substantially uniform diameter. In one embodiment of this type of emulsion the direct positive photographic emulsion comprises fogged silver halide grains, at least 95% by Weight of said grains having a diameter which is within about 40% of the mean grain diameter. Preferably, photographic emulsions of this type comprise reduction and gold fogged silver halide grains and a compound which accepts electrons. The use of loW concentrations of reduction and gold fogging agents, in preparing such emulsions gives unique fogged silver halide grains which are characterized by a very high photographic speed in conventional photographic processing solutions.

To increase sharpness it may be desirable to include an antihalation pigment or dye in the emulsion. Typical dyes and pigments usen in antihalation layers may be used provided they are inert to the emulsion and do not affect the density of the non-image areas. In a preferred embodiment, a carbon pigment is used. A useful amount of antihalation dye or pigment is 20 to 50 grams per silver mole.

It `will be appreciated that any of the conventional silver halide developing agents can be used in the practice of this invention. Such developing agents can be incorporated into the element contiguous to silver halide, e.g., in the emulsion layer or in a contiguous layer. Typical developing agents include hydroquinone and substituted hydroquinones such as bromohydroquinone, chlorohydroquinone, toluhydroquinone, mopholinomethylhydroquinone, etc. It will also be appreciated that an auxiliary developing agent can be used in an amount of 0` to 27%, by weight, of the hydroquinone or substituted hydroquinone in order to improve the speed without affecting the developing reaction.

Typical auxiliary agents include 3-pyrazolidone, developing agents known in the art as well as Elon (N-methylp-aminophenol sulfate), and the like. Particularly useful auxiliary agents are l-phenyl-S-pyrazolidone and 1- phenyl-4,4-dimethyl-3-pyrazolidone.

Polyester, such as polyethylene terephthalate is a particularly useful support for the emulsion in the practice of our invention. However, it will be appreciated that any other suitable support can be used including polymeric support such as polyamides, cellulose esters, polyolefins, etc., paper, glass, etc.

The accompanying drawings illustrate a typical embodiment of our invention.

FIG. l shows exposed photographic emulsion 11 on a transparent support 10 which contains a latent image 14 and non-image areas 15. The emulsion is contacted against a processing sheet or web comprising a transparent support 13 having thereon a gelatin coating 12 having imbibed therein a processing solution.

The processing solution develops: the latent image 14 and complexes the non-image areas 15 in the emulsion 11.

FIG. 2 shows the laminated element in which the emulsion layer 11 contains an image 16 and a complexed non-image area 1S.

The following examples are intended to illustrate our invention but not to limit it in any way:

EXAMPLE 1 Use with direct reversal film A transparent polyester sheet having a gelating coating of 1.68 grams per square foot containing nickel sulde nuclei and with a melting point of about 235 F. is soaked for 10 minutes at 70 F. in a processing solution having the following composition:

Sodium sulfite-48 grams Z-diethylaminoethanol-SS milliliters Potassium bromide-4 grams Guanidinium-S-mercapto-propane sulfonate-40 grams Water to make 1 liter About 6.5 grams of solution per square foot are contained in the web. After squeegeeing, it is rolled into contact with an exposed direct positive silver halide film.

l l The film-web sandwich is kept in contact for one hour. At the end of this time a positive image having a Dmx of 1.6 and a Dmm of about 0.40 results. The laminated sample is kept for 11/2 months Without any significant change in the appearance of the image except for small amounts of crystal growth around the edges of the laminate and a small increase of minimum density due to developer stain.

EXAMPLE 2 A non-nucleated gelatin web The procedure described in Example 1 is repeated except that the processing sheet does not contain added physical development nuclei. It is soaked for minutes at 70 F. in a composition as follows:

Sodium suliite-48 grams 2-diethylaminoethanol-35 milliliters Sodium isoascorbate-24 grams 1-phenyl-3-pyrazolidone-5 grams Potassium bromide- 4 grams Mercaptoacetic acid (80% 10 milliliters Water to make l liter About 6.5 grams of solution per square foot are contained in the Web. The same direct positive iilm is used as in Example 1. After the sheet and film are laminated for one hour, the positive image in the laminate is nearly the same as in Example 1.

EXAMPLE 3 Dual soak system to provide rapid access A usable photographic image in a sheet-film laminate produced in one-half minute is made using the following technique and materials. A direct positive photographic film is soaked for 11/2 minutes at 90 F. in a solution having the following composition:

Sodium sulte-48 grams 2-diethylaminoethanol-35 milliliters Sodium isoascorbate-24 grams 1-phenyl-3-pyrazolidone-5 grams Potassium bromide-5 grams Water to make l liter About 3.0 grams of solution per square foot are contained in the emulsion. A piece of sheet as `described in Example 1 is soaked for 11/2 minutes at 90 F. in a stabilizing solution having the following composition:

Mercaptoacetic acid-90 milliliters Sodium hydroxide-78 grams Water to make 1 liter EXAMPLE l4 The procedure of Example 3 is repeated using the non-nucleated web of Example 2.

The results are as satisfactory as those produced in Example 3.

l 2 EXAMPLE 5 A 35 millimeter strip of gelatin coating containing 1.68 grams per square foot of photographic gelatin having a MP of about 212 F. is soaked in an imbibant containing:

Methylaminoethanol-SOZ (14% SO2 by weight)-300 cc. Hydroquinone-19 g. 2,2-dimethyl-l-phenyl3-pyrazolidine-O.5

3-S-thiuronium propane sulfonate-19-00 Water to 1 liter After soaking for 1 minute at 90 F., 4.5 grams per square foot of solution are contained in the processing sheet. This is laminated to an exposed tine grain silver halide film by passing through a pair of pressure rollers.

The image developed in the exposed layer is of satisfactory speed, contrast and Dmax.

There is no image developed in the sheet. The density of areas corresponding to Dmn values of the image in the photographic element is less than 0.3 when measured by transmitted light through both supports. Thus the sandwich of processing sheet and processed image layer is useful as a single entity without separation of the two. The dry surfaces of the lm support materials can be conveniently handled and viewed Without problems which are associated with handling of wet, tacky surfaces.

Similar results are obtained with the 3-S-thiuronium propane sulfonate of the processing solution is replaced by:

o-Mercapto benzoic acid Mercapto acetic acid Guanidinium-S-mercapto propane sulfonate EXAMPLE 6 A processing sheet as used in Example 5, but containing nuclei for physical development produces similar results. A density of less than 0.3 is produced in the nonimage areas of the processing sheet.

EXAMPLE 7 Laminated elements 35 millimeters wide as described in Examples 5 and 6 are prepared. After being in a laminated condition for 15 minutes, the force necessary to delaminate the members is determined. One end of the lm support, in each instance is attached to a bench top so that it cannot move. The corresponding end of the processing sheet is attached to a spring balance and force applied in a direction 180 to the laminating direction or to the direction of the anchored end of the film support.

The following values are found:

Examples: Delaminating force, g. 5 42 The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as dened in the appended claims.

We claim:

1. In a processing method in which an exposed radiation sensitive silver halide layer is developed by contacting with a processing sheet having imbibed therein a processing solution, the improvement comprising employing in the processing solution a water soluble silver salt stabilizing agent which forms a substantially water insoluble silver salt compound, such that the density of the undeveloped areas is no greater than 0.50.

2. A processing method of claim ll in which the said silver halide stabilizing agent has a formula RSH where R is any aliphatic or cyclic group, and the silver compound has the formula RSAg.

3. A processing method of claim 1 in which the said silver halide stabilizing agent is 3-S-thiuronium propane sulfonate.

4. A processing method of claim 1 in which the said processing sheet has imbibed therein about 3.5 to about 6 grams per square foot of processing solution.

5. A processing method of claim 1 in which the said processing sheet comprises a polyester support.

6, A processing method of claim 1 in which the said processing solution contains the following components per 1000 parts by weight of Water:

Parts by `Weight Silver halide developing agent 5-40 Aliphatic hydroxyamine-sulfur dioxide addition product 50-400 Silver salt stabilizing agent 5-300 7. A processing method of claim 1 in which the processing solution contains the following components per 1000 parts by Weight of Water:

Parts by Weight Aliphatic hydroXyamine-sulfur dioxide addition product 50-400 Silver salt stabilizing agent 5-300 8. A processing method of claim 1 in which the radiation sensitive silver halide layer is a direct positive silver halide emulsion.

9. A processing method of claim 1 in which the silver halide layer is coated over a colloid layer.

10. A processing method of claim 1 in which the silver halide layer is coated over a gelatin layer.

11. A processing method of claim 1 in which the processing element carries therein silver precipitating nuclei.

12. A processing method of claim 1 in Which the silver halide layer has a colloid overcoat.

13. A photographic element comprising an exposed, developed radiation sensitive silver halide layer having laminated thereto a processing sheet comprising a liquid absorbing colloid layer, said silver halide layer having been developed by a processing solution imbibed in said processing sheet and comprising a Water soluble silver salt stabilizing agent which forms a substantially Water insoluble silver salt compound, such that the density of the undeveloped area is not greater than 0.50, said Water soluble silver halide stabilizing agent being a compound of a Water soluble compound having the formula RSH, where R is an aliphatic, cyclic or heterocyclic group.

14. An element of claim 13 in which said layer is on a polyester support.

15. An element of claim 13 in which said stabilizing agent is a 3-S-thiuronium propane sulfonate.

16. An element of claim 13 in which said stabilizing agent is a guanidiniurn-S-mercapto propane sulfonate.

References Cited UNITED STATES PATENTS 2,476,240 7/ 1949 Famulener ll7--8lX 2,867,542 1/1959 De Keyser et al 117-81 2,875,048 2/1959 Haist et al. 96-61 3,179,517 4/1965 Tregillus et al. 96-29 3,220,839 1l/1965 Herz et al 96-61 FOREIGN PATENTS 884,390 12/1961 Great Britain 96-61(M) NORMAN G. TORCHEN, Primary Examiner I. D. WINKELMAN, Assistant Examiner U.S. Cl. X.R. 96-29 

